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When Izuku got nicked and paralyzed he’d thought he’d be out of the fight. Thought he’d be stuck watching Todoroki struggle while he was unable to help.
But.
“I'm not sure why but I’m able to move now!”
“So he has a time limit.” Todoroki says.
“No.” Native manages to groan. “That kid should have been the last one to be freed. I still can’t move a muscle.”
The Hero Killer shoves Izuku away and he hits the ground hard.
“Midoriya dodge!”
He ducks aside as Todoroki sends a wave of ice to push the killer back.
Izuku coughs into his fist before sharing his thoughts. “He swallows a person's blood to freeze them but I was the one freed first. I’ve got three different guesses why. His quirk could be less effective the more people he uses it on. The amount ingested could play into how it works. Or there could even be a difference based on the person's blood type.”
“If it’s the last one” Native whispers “my blood type is B”
“I’m type A” Iida forces out.
Stain grins. “So you figured it out. Bravo. Very impressive.”
“It doesn’t really help us that much to know how his quirk works though. I mean worst case we’ve established that O wears off pretty fast so just in case…”
“Yeah.” Todoroki nods. “I’m O too so between the two of us he won’t be able to keep us down long.”
Izuku’s brain screeches to a halt.
“Y-you’re O??? But isn’t your father AB???”
Stain scratches at his chin. “Yeah. The only way for an AB to genetically have an O kid is if he is Cis AB. It’s a really rare mutation though so maybe Endeavor isn’t really his father.”
Izuku can feel his jaw drop. “No way! That’s crazy! That kind of information doesn’t exist on any of the hero forums!”
Stain nods sympathetically. “Yeah well hero forums are mostly run by fans since the official sites don’t want to provide as much information due to” he pauses to spit the word. “privacy.”
“Still though! Either Endeavor has Cis AB or Todoroki’s father is a different fire user.”
Stain huffs. “You’re assuming that his quirk isn’t just the mutated form of a water quirk.”
“But the only pros I know with water types are Manual and Backdraft and they’re both type A!”
“Manual is way too young but it would still be plausible for Backdraft, especially since we never see his face. It all depends on whether his mother is O though... Well kid?”
Todoroki jolts at the sudden attention. “Uh… I don’t know?”
Stain flicks his tongue. “Couldn’t Endeavor have just adopted him once his quirk came in?”
Izuku shakes his head, finger tapping at his lower lip. “No, powerful quirk or not Endeavor would be too proud to pick someone random off the street. They’d need to have some sort of legacy to be worthy of his attention. Besides, Todoroki does look like his mother…”
Stain slides his blade back into its sheath. “I think I heard somewhere that none of the Todoroki kids look alike. You think Endeavor is sterile and they’re all from different red headed fire users?”
Todoroki lets out a strangled sound as Native and Iida stare in shock at the turn of events.
Izuku nods. “Assuming Rei is Type O then as long as they aren’t AB there would be a fifty fifty chance of Todoroki being O as well.”
Stain scoffs. “Not like there are many other fire users with AB. It’s just Drago isn’t it?
Izuku hums. “And Flare-Fest but he’d be way too old.”
“So Crackle?”
Izuku’s face twists. “Not Crackle! He’s been in a committed relationship since before Todoroki was born! If he cheated with Endeavor’s wife then I have lost all respect for him!”
“Valid. Didn’t he just have his own kid?”
“Yeah! She’s got his flaming hair and it’s so adorable I can’t get over it!”
Stain snaps his fingers. “Inferno!”
Izuku hums thoughtfully. “Possible. I was leaning more towards Combustion though.”
Stain snears. “Combustion dyes his hair! I swear, I just had this conversation last week on Fount-“
“-of Useless Hero Knowledge?”
The two stare at each other in silence before-
“A-All Fight???” Izuku stammers.
“Small Mite?” Stain gasps.
“What a twist.” Todoroki murmurs.
Beside him Iida and Native have regained the ability to move but don’t seem to have noticed.
“Wait!” Stain points a finger at Izuku accusingly. “You said you were quirkless!”
“I-I w-was! I s-swear! My quirk came in late, after I bulked up for the entrance exam! Anytime before that and it would have blown my limbs off.”
Iida and Todoroki stare at the nonchalant way Izuku says that but Stain simply nods.
“Oh yeah. I saw that at the festival. Crazy bone breaking kid right? Almost didn’t recognize you when you sparked in here all badass.”
Izuku flushes and ducks his head. “I’ve been working on it…”
There’s a loud screeching noise and a winged Noumu appears overhead. It swoops low towards Izuku and Stain simply tosses a knife at it without breaking the conversation. “Oh hey, did you ever show that Kacchan kid who’s boss? I swear, if you weren’t so opposed I could’ve messed him up for you.”
“God, I can’t believe all this time you were offering to actually hurt him. I thought you were just a big college kid who would show up out of nowhere to scare him or something!”
The Noumu crashes into a wall and slides down still screeching.
Stain throws another knife at it. “Come on Kid, you know that wouldn’t have scared him.”
Izuku shrugs. “True but it’s a moot point anyway. I beat him in school a couple of times and things aren’t so bad now.”
Stain’s eyes narrow. “Because you have a quirk now?”
Izuku picks at his cuticles. “I… like to think that’s not the only reason…”
Stain grunts but doesn’t reply.
There’s shouting coming from the street and the unmistakable voice of Endeavor is heard.
Stain sighs before retrieving his knives from the now dead noumu. “Guess that’s my cue.”
“Running away Villain?” Native shouts with false bravado.
The Hero Killer laughs. “You’re just asking for me to end you! But sadly I’m not in the mood right now.” He sheathes his weapons and looks back at Izuku. “I’ll have to make a new profile since they all heard my username but I’ll message you later.” He jerks his head towards the rapidly approaching flame hero. “Ask him about the Cis AB alright? I’ll stick around so I can see his face.”
Izuku snaps a mock salute. “Will do!”
Todoroki shakes his head incredulously. “What even is your life Midoriya?”